It is believed that many of the UK's 17,000 heat network operators failed to respond to the four-yearly Duty of Notification process by the December 31, 2019 deadline. The Office for Product Safety and Standards (OPSS), which enforces the regulations, has begun issuing formal warnings to these non-compliant heat networks.

The guide details the urgent action heat network suppliers need to take now to comply with the legislation. It also explains the future requirements that are expected to be introduced later in 2020, following the current Heat Network Market Framework consultation period.

Ian Allan, head of market strategy for Switch2 Energy, explained: 'The market framework is the main vector for proposed changes in heat network legislation, including extending provisions on meter accuracy, maintenance and billing. One of the most significant areas of consultation is a requirement to retrofit final customer meters to non-metered homes, where a revised new feasibility tool shows that it is viable.

'This will replace the original tool, which was suspended in 2015 and has now been re-designed. When the new tool is released, heat suppliers with non-metered networks will have to test the scheme to determine whether it is viable to install meters or heat cost allocators and then take any required corrective action. This test must be repeated every four years.'

It is already compulsory for new build projects and most buildings undergoing major refurbishment to fit final customer meters. It is also mandatory for all heat networks to install point of entry meters, which record the amount of heat supplied into the building.

In addition, actual meter readings rather than estimates, must be used for bills, which must be transparent and informative. Customers are entitled to receive a detailed bill based on actual consumption at least once a year, or quarterly if they receive bills electronically.

'The legislation drives best practice in smart metering and billing and pays off in terms of improved heat scheme efficiency, emissions reductions and better customer service', added Ian Allan. 'Innovative new pay-as-you-go smart meters can simplify the compliance process and drive huge cost and carbon savings by giving customers full visibility of how much energy they are using and how much it's costing them.'